Heat transfer unit

ABSTRACT

A heat exchanger for heating a fuel-air mixture by exhaust gases of an engine. The exchanger is generally rectangular with heat exchanger tubes extending therethrough from an inlet exhaust gas manifold section to an outlet exhaust gas manifold section. The exchanger is adapted to be mounted between the carburetor and intake manifold of the engine.

United States Patent 1 Streitz 1 Mar. 12, 1974 1 1 HEAT TRANSFER UNIT [76] Inventor: Federico E F. Streltz, 10828 Otsego St, North Hollywood, Calif. 91601 [22] Filed: Apr. 10, 1972 21 Appl. No.: 242,684

[52] US. Cl 165/52, 165/109, 165/179 [51] Int. Cl. F02n 31/08 [58] Field of Search 165/51, 52, 109, 109 T,

[56] References Cited UNITED STATES PATENTS 2,144,506 l/l939 Potter 165/179 Chapman 165/52 Ulrich 165/52 Primary ExaminerCharles Sukalo Attorney, Agent, or FirmLyon and Lyon [5 7] ABSTRACT A heat exchanger for heating a fuel-air mixture by exhaust gases of an engine. The exchanger is generally rectangular with heat exchanger tubes extending therethrough from an inlet exhaust gas manifold section to an outlet exhaust gas manifold section. The exchanger is adapted to be mounted between the carburetor and intake manifold of the engine.

2 Claims, 3 Drawing Figures HEAT TRANSFER UNIT The present invention relates to improved means and techniques for increasing the efficiency of operation in an internal combustion engine and involves the concept of using the heat from exhaust gases of the engine to preheat the fuel-air mixture entering the engine.

An object of the present invention is to provide an improved heat exchanger for these purposes which is particularly useful with fuels that have a low percentage of unburnables or residues of any kind.

Another object of the present invention is to provide a heat exchanger for these purposes which improves performance of the engine regardless of the character of the fuel of the engine, using fuels with a low percentage of unburnables or residues of any kind.

Another object of the present invention is to provide an improved heat exchanger for these purposes which is relatively small, compact, and easily installed between the carburetor and its engine.

Another object of the present invention is to provide an improved heat exchanger which will achieve a low exhaust emission of smog creating agents such as nitrogen oxides, carbon oxides and unburned hydrocarbons.

Another object of the present invention is to provide an improved heat exchanger which will make possible a greater B.T.U. output resulting in improved fuel economy.

The features of the present invention which are believed to be novel are set forth with particularity in the appended claims. This invention itself, both as to its organization and manner of operation together with further objects and advantages thereof, may be best understood by reference to the following description taken in connection with the accompanying drawings in which:

FIG. 1 is a view in elevation illustrating the heat exchanger of the present invention mounted on an internal combustion engine between its carburetor and its fuel-air inlet.

FIG. 2 is a sectional view taken substantially as indicated by the line 22 in FIG. 1.

FIG. 3 is a sectional view taken substantially as indicated by the line 33 in FIG. 2.

The heat exchanger is formed of good heatconducting material which may, for example, be copper, brass, stainless steel and as seen has a rectangular body portion from which tubular pipe portions 11 and 12 extend from opposite ends.

The heat exchanger is mounted in the position shown in FIG. 1 using four mounting bolts 13 which extend through aligned apertured portions of the mounting flange A of carburetor 15, through apertured portions 14 of the heat exchanger and which are threaded in the engine block 16 or its fuel intake manifold.

In so mounting of the heat exchanger having the general reference number 9, there is alignment between the fuel-air outlet of the carburetor 15 and the fuel-air intake manifold 16A of the engine 16.

The pipe section 11 serves as a conduit for the flow of exhaust gases into the heat exchanger, and the other aligned pipe section 12 serves as the exhaust gas outlet of the heat exchanging unit. Well-known techniques may be used in connecting the pipe sections in the exhaust system of the automobile such that all or only part of the exhaust gases flow through the heat ex changer.

The fuel-air mixture in its travel from the outlet opening of the carburetor 15 to the intake manifold enters the two circular openings 10A, 108 in the top plate 10C, and the heated fuel-air mixture leaves through a like pair of openings 10D, 10E in the bottom plate 10F in its passage to the engine intake manifold. As seen in FIG. 2, the exhaust gas inlet pipe 11 conducts exhaust gases to an internal generally rectangular portion 10G which is in the nature of an inlet manifold which is defined by the upper and lower wall portions 10C, 10F, wall 10H and internal apertured wall 10] upon which one end of each of four generally square conduits 10K, 10L, 10M and ION are supported. These heat exchange conduits or tubes l0K-l0N extend parallel with each other and parallel with the axis of conduits 11 and 12 and terminate at the apertured wall 10F which supports the other ends of such tubes 10K-10N and which forms one wall portion of an outlet manifold lOQ which is defined also by end wall 10R and the upper and lower wall portions 10C, 10F. These rectangular tubular portions l0K-10N are interconnected at various points along their lengths by discontinuous webs which are made discontinuous so as to impede as little as possible the flow of the fuel-air mixture past the tubes 10K-10N, through the heat exchange unit. These web portions between adjacent tubular sections 10K-l0N and between adjacent side walls are designated by reference numerals 10S, and the web portions which serve to connect the tubular portions 10K, 10N to the upper and lower walls 10C and 10F are designated by the reference numeral 10T. As mentioned previously, these web portions are not continuous but are sufficiently long to provide suitable bracing and rigidity between tube sections l0K-l0N and adjacent walls defining the rectangular portion 10.

It is noted that each of the tubular elements or conduits 10K, 10L, 10M and 10N contain baffles 10W spaced internally and alternately attached to different side wall portions thereof to provide a tortuous path indicated by the arrows 10X for the flow of exhaust gases so as to achieve a turbulent exhaust gas flow therein and increased surface contact with the tubular elements so constructed.

While the particular embodiments of the present invention have been shown and described, it will be obvious to those skilled in the art that changes and modifications may be made without departing from the invention in its broader aspects and, therefore, the aim in the appended claims is to cover all such changes and modifications as fall within the true spirit and scope of this invention.

I claim:

1. A heat exchanger for internal combustion engine in which fuel-air mixture is preheated by exhaust gases; a hollow housing structure; inlet and outlet exhaust gas conduit means extending from said hollow housing; means defining an inlet manifold portion in said housing with which said inlet exhaust means is in direct communication; means defining an outlet manifold portion in said housing with which said outlet exhaust gas means is in direct communication; a plurality of elongated tubular elements extending between said inlet and outlet manifold portions and being in communication with the same; and fuel-air inlet and outlet openings in said housing on opposite sides of said tubular elements such that the fuel-air mixture entering its inlet and leaving its outlet is heated by the exhaust and also discontinuous web portions interconnect said tubular portions to internal wall portions of said hollow housing.

2. A heat exchanger as set forth in claim 1 in which open ends of said tubular elements are supported in apertured wall portions which define in part said inlet manifold portion and said outlet manifold portion respectively. 

1. A heat exchanger for internal combustion engine in which fuel-air mixture is preheated by exhaust gases; a hollow housing structure; inlet and outlet exhaust gas conduit means extending from said hollow housing; means defining an inlet manifold portion in said housing with which said inlet exhaust means is in direct communication; means defining an outlet manifold portion in said housing with which said outlet exhaust gas means is in direct communication; a plurality of elongated tubular elements extending between said inlet and outlet manifold portions and being in communication with the same; and fuel-air inlet and outlet openings in said housing on opposite sides of said tubular elements such that the fuel-air mixture entering its inlet and leaving its outlet is heated by the exhaust gases flowing through said tubular elements; said hollow housing being defined by at least two parallel walls in which said fuel-air inlet and fuelair outlet are disposed and aligned apertured portions in said parallel walls through which fastening means may extend; said tubular elements being generally rectangular in cross-section with a pair of diagonal corners of such rectangle being aligned in a direction extending from said fuel-air inlet to said fuelair outlet; and discontinuous web portioNs interconnect adjacent tubular elements and also discontinuous web portions interconnect said tubular portions to internal wall portions of said hollow housing.
 2. A heat exchanger as set forth in claim 1 in which open ends of said tubular elements are supported in apertured wall portions which define in part said inlet manifold portion and said outlet manifold portion respectively. 